"Even if the law had been struck down, there are so many changes already occurring in the health care delivery system, which are amplified by the Affordable Care Act, that that train has already left the station," said Arthur Gianelli, chief executive of Nassau University Medical Center in East Meadow.

North Shore-LIJ and other hospitals are undergoing a vast transformation, in part prompted by the federal health care overhaul. Instead of being reimbursed for each treatment -- called fee-for-service -- doctors and hospitals will be rewarded for keeping patients healthy and out of the hospital.

Kevin Dahill, chief executive of the Nassau-Suffolk Hospital Council, said that while the decision "should bring some clarity," exactly how the act will be implemented in the state remains less clear.

"What I think remains is very complicated, with a lot of unknowns," he said. For example, as the state sets up an insurance exchange -- a state-based, competitive marketplace for health insurance that will begin in 2014 -- "what requirements will it make of providers? All that remains to be seen."

Dahill said he was also concerned about the Supreme Court's decision to curtail the mandate on states to provide expanded coverage to low-income individuals under the Medicaid program.

"New York is one of a handful of states that already go above and beyond the federal requirements," he said.

Assemb. Richard Gottfried (D-Manhattan), chairman of the State Assembly's health committee, appeared less worried. "It's hard to imagine New York wouldn't take advantage of the Medicaid expansions," he said.

"The bottom line," Gottfried said, is the decision is "good for the country and good for New York."

But Martin Cantor, an economist and director of the Long Island Center for Socio-Economic Policy, predicted that Long Islanders eventually would end up paying more taxes because there won't be enough money to pay for the health care expansion.

"Long Island will wind up sending more money to Washington," he said. "Just as there's a Social Security deficit, this will run at a deficit as well. They will tax us to keep this solvent."

Gwen O'Shea, chief executive of the Health and Welfare Council of Long Island, said the decision "means people aren't going to have to gamble with their health anymore. People aren't going to have to leave it up to chance."

Elisabeth Benjamin, vice president of the Community Service Society of New York, a nonprofit advocacy group for the poor, agreed: "At the end of the day, the most important thing is 1 million people in New York stand to get covered."

Raymond Keating of Center Moriches, chief economist for the nonprofit Small Business and Entrepreneurship Council based in Washington, D.C., predicted "the debate will go on."

"Obamacare is a vast expansion of federal power. . . . In the end, it's all going to be decided in November."